1. Field of the Invention
The present invention relates to a rotating shaft that receives a driving force of a power source and a pulley around which a belt for transmission of the driving force is wound.
2. Description of Related Art
A straddle-type vehicle such as a motorcycle may include an engine and a continuously variable transmission (CVT) for stepless change in reduction ratio. CVTs generally include a-belt for transmission of driving force of an engine to a drive wheel, and a moving pulley around which the belt is wound that moves in an axial direction to vary a diameter of the portion on which the belt is stretched. In some conventional CVTs, keyways are formed on a boss of a moving pulley and a crank shaft onto which the boss is fitted. Keys are inserted into the keyways from radially so that the moving pulley and crank shaft rotate integrally (see, for example, JP-A-2006-118630).
In JP-A-2006-118630, however, the work of assembling the crank shaft and moving pulley is complex. When the crank shaft and moving pulley are to be assembled, either the crank shaft or the moving pulley is rotated so that positions of the keyways are in agreement. While holding this state, a key is inserted into the keyways. In order to prevent coming-off of the key, the key is generally press fit into either the keyway of the crank shaft or the keyway of the moving pulley. However, after the keyways are caused to positionally agree with each other, they sometimes get out of position before the key is press fitted. The crank shaft or moving pulley must then be rotated again to bring the keyways back into positional agreement, thus making the work complex.